transmission between neurons

Question 1

how do neurones send messages?

Answer 1

via synaptic transmission

Question 2

outline the steps of transmission between neurones

Answer 2

• neurotransmitters are released from one neurone
• neurotransmitters travel across synaptic junction/cleft
• neurotransmitters to post-synaptic receptors of another neurone
• initiates a reaction
• results in post-synaptic potentials

Question 3

what are neurotransmitters?

Answer 3

chemical messengers that travel from neurone to neurone

Question 4

what is the synaptic cleft?

Answer 4

gap between two neurones

gap between the terminal button of the presynaptic neurone and the postsynaptic membrane

Question 5

how big is the synaptic cleft?

Answer 5

20 nanometres

Question 6

what are synaptic vesicles?

Answer 6

contains neurotransmitters

binds to receptor, releasing membrane

Question 7

outline the process of synaptic transmission

Answer 7

• action potential at terminal button
• this causes calcium channels to open
• calcium ions enters terminal button
• calcium ions causes vesicle to fuse with membrane
• resulting in pores opening
• neurotransmitters are released into synaptic cleft via process of exocytosis
• neurotransmitter diffuses across synaptic cleft
• neurotransmitter binds to postsynaptic membrane
• causing postsynaptic channels to open
• flow of ions result in excitatory / inhibitory post synaptic potentials

Question 8

what effect does neurotransmitters binding to post-synaptic membrane have on PSP?

Answer 8

• binding alters the membrane potential of the post synaptic membrane
• this results in either an excitatory postsynaptic potential (a PSP that makes it more likely to fire an action potential)
• or results in an inhibitory postsynaptic potential (a PSP that makes it less likely to generate an action potential)

Question 9

how does a neurotransmitter bind to binding site on post-synaptic membrane?

Answer 9

lock and key

Question 10

what effects the postsynaptic potential?

Answer 10

which ion channel (lock) is open is what will determine the PSP

Question 11

identify two types of receptors

Answer 11

1/ ionotropic receptor

2/ metabotropic receptor

Question 12

explain what an ionotropic receptor is

Answer 12

• type of receptor containing binding site AND ion channel
• opens when molecule attaches to binding site

Question 13

explain what a metabotropic receptor is

Answer 13

• contains binding site
• initiates chain reaction
• chain reaction will open ion channels
• requires energy
• postsynaptic potential is slower than PSPs produced by ionotropic receptors

Question 14

define ‘reuptake’

Answer 14

this is where transmitter is taken back up by presynaptic terminal via transporter molecules

Question 15

define ‘enzymatic deactivation/degradation’

Answer 15

this is where transmitter is broken down by an enzyme

Question 15

define ‘enzymatic deactivation/degradation’

Answer 15

this is where transmitter is broken down by an enzyme

Question 16

what are excitatory PSPs?

Answer 16

PSPs that increase likelihood of neurone firing

Question 17

what are the inhibitory PSPs?

Answer 17

PSPs that decrease the likelihood of neurone firing

• these do not always inhibit behaviour
• inhibition of inhibitory neurones = more likelihood of behaviour
• excitatory of inhibitory neurones = less likelihood of behaviour

Question 18

what is integration?

Answer 18

summation of PSPs in control of neurone firing = integration

ability to integrate multiple PSPs at multiple synapses = summation

Question 19

outline the neurotransmitter GABA

Answer 19

• most abundant inhibitory neurotransmitter
• reduces chance of neuronal firing
• important role in brain development

Question 20

outline the neurotransmitter Glutamate

Answer 20

• most abundant excitatory neurotransmitter
• can bind to number of receptors
• important in learning and memory

Question 21

outline the neurotransmitter Acetylcholine (ACh)

Answer 21

• found in CNS and PNS
• works primarily in muscles
• helps translate our intentions to move into actions

Question 22

outline the neurotransmitter dopamine

Answer 22

• pleasure chemical
• released when mammals receive reward
• has responsibility for motor control

Question 23

outline the neurotransmitter serotonin

Answer 23

• regulation of mood
• help manage eating, sleeping, memory
• lack of serotonin = depression

Question 24

what is an antagonist

Answer 24

drug that blocks neurotransmitters

Question 25

what is an agonist

Answer 25

• drug that mimics neurotransmitter
• enhances synapse function